A spy enables a sneaking commander to gain more information about hostile provinces they enter. They are also able to perform some active acts of subterfuge.

A spy in a hostile province does the following:

• Reduces scout report inaccuracy to ±10% of the unit's visible, in contrast to a regular scout's 30%¹⁾
• Reveals all discovered magic sites in the province, even without full ownership of the province.
• Displays the scales in the province.
• Displays full details of the province's population, income, unrest, resources, supplies, and recruitment points

Additionally, spies can perform the the following actions:

• Instil Uprising: Adds d20 (open ended) unrest to the province²⁾.
• Infiltrate: Fails if not used on a nation's capital. Has a 50% chance to succeed³⁾. Success updates score graphs for that nation: provinces, forts, and income are always obtained; gem income and research are obtained only if the spy has magic paths, and dominion is only obtained if the spy is a priest.